/Engine/Source/Runtime/Engine/Public/Animation/SkeletonRemapping.h
Get the specified additive transform retargeted from the source skeleton onto the target skeleton, corrected for differences between source and target rest poses
Transform mapped onto the target skeleton
FTransform RetargetAdditiveTransformToTargetSkeleton ( int32 TargetSkeletonBoneIndex, const FTransform & SourceTransform ) const